Thread-controlling mechanism for sewing-machines



Patented m. 2 4, 399.

J. E. BERTRAND. G MECHANISM'FOR SEWWG- MACHINES.

plicat'xon file'd. June 8, 1.898.!

THREAD GONTROLLIN (No Modem Y NITED STATES ATENT nrron.

JOSEPH ELI BERTRAND, OF BOSTON, MASSACHUSETTS.

SPECIFICATION forming part of Letters Patent No. 618,372, dated January24, 1899.

Application filed June 8, 1898. Serial No. 682,927. (No model.)

To all whom, it may concern.-

Be it known that I, JOSEPH ELI BERTRAND, of Boston, in the county ofSuffolk and State of Massachusetts, have invented certain new and usefulImprovements in ThreadMeasuring and Looking Devices for Sewing-Machines,of which the following, taken in connection with the accompanyingdrawings, is a specification.

My invention relates to thread measuring and locking devices for sewingmachines; and it consists in certain novel features of construction,arrangement, and combination of parts, which will be readily understoodby reference to the description of the accompanying drawings and to theclaims hereto appended and in which my invention is clearly is asectional plan showing the novel features of my invention. Figs. 3 and 4are respectively a plan and an elevation of the adj ustablethread-guiding sheave, its locking-pawl, and a portion of itscarrying-arm; and Fig. 5 is an elevation of the thread-measuring finger.Figs. 3, 4:, and 5 are drawn to an enlarged scale.

In the drawings, A is a portion of the column upon which themachine-head is mounted, and B the base of the head-frame.

O is the cam-shaft, mounted in suitable bearings in columns carriedplate, but not shown.

D is a stand secured upon the base-plate B at the rear of the cam-shaftand cams, and having set therein the stud E,upon which are mounted uponopposite sides of said stand D the levers F and G, only a portion of theformer being shown.

II is a lever fulcrumed at a and having secured thereto the worksupport'or table 5 and provided at its lower end with a lug c, whichengages the slotted front end of the sliding bar I and has mounted upona stud set therein a roll d, as shown, and a is the presser-foot.

J is .a hand-lever fulcrumed at e and arranged to act upon the roll d onthe lever H to move said lever H around its fulcrum and move the slidingbar I to the rear and proby said basevided with the lifter-toe f to actupon the short arm of the locking-lever K to lift its heel g fromcontact with the plate h and un* lock the bar I against the tension ofthe spring L, mounted upon the upper end of the rod 12 between thetension-adjusting nut at the upper end of said rods, and the bearing ofsaid rodin the hub of the stand D, the lower end of said rod beingconnected to the rear end of said lever K, said heel g also being raisedonce in each revolution of the shaft 0 by the cam g acting upon a truckmounted upon the lever K between said rod 19 and the heel g of saidlever, as shown in dotted lines in Fig. 1.

M is a portion of a bracket for supporting the wax-pot, (not shown,) andM is a smaller bracket carrying at its rear end a spindle 2', upon whichis mounted the tension-wheel j, the friction-disk j, the spring and thetension-adjusting nut 7' all of well-known con struction.

The levers H, J, andK are fulcrumed upon studs set ina standard N,projecting upward lfrom the base-plate B, the outline of a portion ofwhich is shown in dotted lines in Fig. 1 and in full lines in Fig. 2.

The sliding bar I has formed in one piece therewith or secured theretothe rearward extension I, having set therein near its rear end a fixedstud is, upon which is mounted the thread guiding sheave Z, upon oneside of the groove in whichis formed a series of ratchet reeth, withwhich the stop pawl engages to prevent a backward rotation of saidshield, said pawl being pressed into engagement with said-teeth by thespring m, and n is a wire guard secured to the stud 70 by the screw 11to prevent displacement of the thread on said sheave.

The needle-thread m in passing from the wax-pot orthe source of supplyto the work on the work-support passes once around the tension-Wheel j,thence to and once around the sheave Z, and thence in any well-knownmanner to the work.

The lever G has secured to its rear end the brake-shoe 0, which when therear end of said lever is depressed bears upon the thread on thetension-wheel and clamps it thereto, so

as to prevent said thread being drawn from said wheel or the source ofsupply when the needle is pulling the loop through the work, when theshuttle is passing through and expanding said loop, or when the stitchis being set. The forward end of said lever G carries a cam-truck, whichis acted upon by the cam 0 to move said lever in one direction, it beingmoved in the opposite direction by the tension of the spring 1), saidcam O and spring 1) being shown only in dotted lines in Fig. 1.

The lever F is vibrated by the action of the cam-path q upon a cam-truck 7", carried by said lever, and indicated by a dotted circle inFig. 1. The forward end of said lever (which is omitted from thedrawings) is connected to and imparts motion to the awl-segment (notshown) in a well-known manner, and said lever has a rearwardlyprojecting arm, in which is set the pendent fingers, the lower end ofwhich is forked, as shown in Fig. 5, to engage the thread as, betweenthe tension-wheel j and the sheave Z, when the rear end of the lever Bis moved downward, and depress it, thereby drawing from saidtension-wheel and the source of supply the necessary amount of thread toform a stitch. said downward movement of the finger s takin g place whenthe brake-shoe 0 is raised from contact with the thread on thetension-wheel.

The remaining parts of the sewing-machine to which the parts hereindescribed appertain and with which they cooperate are shown anddescribed in an otherapplication of mine, filed June 8, 1898, Serial No.682,928, and the parts herein described and claimed are shown anddescribed, but not claimed, except in special combinations, in saidother application.

The operation of myinvention is as follows: The needle-thread 00 beingdrawn from the source of supply through the wax-pot (not shown) to andonce around the tension-wheel j, thence to and once around the sheave Z,

and thence to the work in any well-known manner, as hereinbeforedescribed, and the machine being in operation sewing Work placed betweenthe presser-foot and the worksupport, at the proper time in eachrevolution of the shaft (1 in the direction indicated by the arrow onFig. 1 the brake-shoe 0 is raised from contact with the thread on thetension-wheel, and at the proper time after said brake-shoe has beenraised the measuring-finger s is moved downward by the action of thecam-path (1 upon the lever F and engages the thread 00 between thetension-wheel and the sheave Z and depresses it to a sufficient distanceto draw from said tension-wheel and the source of supply an amount ofthread sufficient for the formation of a stitch, the sheave Z beinglocked against-rearward revolution by the .pawl is engaging theratchetteeth on the sheave, and thus preventing any thread being drawnfrom in front of said sheave. Later in the revolution of the shaft 0 andwhile the needle is drawing the loop of thread through the work thebrake-shoe 0 descends upon the thread in the groove of the tension-wheeland locks the thread against being drawn from said tensionwheel andsource of supply while the shuttle is passing through said loop andwhile the stitch is being set, as fully described in said before-citedother application.

The work-support I) being secured to the pivoted lever H, one arm ofwhich is connected to the bar I, which is pressed toward the front bythe spring t, and the arm I, which carries the sheave Z,being formed inone piece with or secured to and movable with the bar I, it follows thatif the work being sewed varies in thickness the feeding of the work froma position with a thin portion thereof between the work-support andpresser-foot to a position with a thicker portion between said partswill cause a depression of the worksupport 1), thereby moving the bar II and the sheave Z toward the rear, the heel g of the locking-lever Kbeing raised by the action of the cam g upon said lever to release saidbar and permit said rearward movement. The rearward movement of thesheave Z, which shortens the distance between said sheave and thetension-wheel j, causes the downward movement of the measuring-finger sto draw an increased quantity of thread from the tension-wheel and thesource of supply by virtue of the facts that the distance between thesheave Z and the tension-wheel is lessened, while the downward movementof the measuring-finger is the same, and that the sheave Z is lockedagainst rearward revolution, and the thread being wound entirely aroundsaid sheave must cross on the top of the sheave,

and when the finger s descends and presses upon said thread it is drawnclosely into the angle of the groove of said sheave, causing thecrossing portions of the thread tobind each other firmly againstslipping, and as the brake at this time is removed from thetension-wheel the necessary thread is drawn from said tension-wheel andthe source of supply.

If the work is fed from a thick to a thin portion, the reverse actiontakes place and a less length of thread is drawn from the tension-wheeland the source of supply, the forward movement of the bar I Iand thesheave Z being effected by the reaction of the spring t, connected atone end to the barI and at its other end to a fixed part of the machine.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is-

1. In a thread-measuring device for sewingmachines the combination witha frictional tension-wheel, of a thread-guiding sheave in near proximityto said tension-wheel; means for locking said sheave against backwardrevolution a thread-en gagin g fin ger arranged above a line tangent tothe tops of said sheave and tension-wheel, and having its lower endforked or notched to engage the thread between said sheave andtension-wheel in near proximity to said tension-wheel; and means forreciprocating said finger and causing it to IIO engage and depress saidthread below a line tangent to said tension-wheel and sheave and thusdraw thread from said tension-wheel and the source of supply.

2. In a thread measuring and locking de vice for sewing-machines thecombination with a frictional tension-wheel, and a worksupport andpresser-foot cooperating to clamp the work, of a thread-guiding sheavein near proximity to said tension-wheel but between it and saidwork-support freely revoluble in a forward direction; means for lockingsaid sheave against backward revolution; a thread-measuring fingerarranged to engage the thread between said tension-wheel and sheave;means for reciprocating said finger and causing it to depress saidthread to draw thread from the tension-wheel and the source of supply;and mechanism between the axis of said sheave and the work supportconstructed and arranged to cause the downward and upward movements,respectively, of the work-support, due to varying thicknesses of thework, to move the axis of said sheave toward and from saidtension-wheel, and thus cause the amount of thread drawn from saidtension-wheel to correspond with the amount required to form a stitch.

3. The combination of the tension-wheelj; the pivoted lever G providedwith a camtruck; a cam constructed and arranged to act upon said truckto move said lever in one direction; the spring 19 arranged to move saidlever in the opposite direction; the brakeshoe 0 carried by said leverand arranged to engage and clamp the thread on said tensionwheel; thereciprocating bar I the sheave Z provided with ratchet teeth and mountedupon a stud set in said bar 1; the pawl it for locking said sheaveagainst backward movement, and pivoted to said bar I the leverF providedwith the cam-truck r; the measuring-finger 8 carried by said lever F andhaving its lower end forked or notched as set forth; and the cam-path qto act upon and vibrate said lever, all substantially as described.

4. The combination of the pivoted worksupport b H; the sliding bar I andextension I; the locking-lever K; the cam g for operating saidlocking-lever; the sheave Z provided with ratchet-teeth; the pawl 7;;the tension-wheelj; the leverF; the measuringfinger 8 carried by saidlever; and the campath q for operating said lever and'finger.

vJune, A. D. 1898.

JOSEPH ELI BERTRANlI Witnesses:

N. O. LOMBARD, E. H. TANSEY.

